Abstract: In view of coking problem S Zorb unit feed heat exchanger, the causes of coking formation were analyzed, and the effect of alkylation desulfurization and olefin reduction on the coking properties of FCC gasoline was studied, and the catalyst, reaction temperature and reaction space velocity for the alkylation of FCC gasoline were optimized. The results showed that Amberlyst 35 resin had the best catalytic performance for FCC gasoline alkylation reaction among the four selected catalysts. The optimized alkylation temperature of FCC gasoline was 90 ℃, the space velocity was 1.0 h^-1 and the pressure was 0.5 MPa. Under optimum conditions, the coking amount of the treated gasoline on an iron disc was significantly reduced, but the octane number and Reid vapor pressure were also decreased. The octane number and Reid vapor pressure of the gasoline could be increased by adding C₄ mixed hydrocarbon to the gasoline after the alkylation reaction, so that the alkylated gasoline could meet the quality standard.

Key words: S Zorb, coking in heat exchanger, alkylation reaction, resin, catalyst